Analyzing circuit of wheel speed sensor signal

Abstract

The utility model provides a wheel speed sensor signal analysis circuit, which is used for enabling the circuit to be compatible with a standard current type wheel speed sensor and an AK protocol current type wheel speed sensor at the same time, and comprises an overcurrent protection module, a current sampling resistor and a wheel speed signal output module, the overcurrent protection module is used for closing the connection with the wheel speed signal output module when the signal of the wheel speed sensor is short-circuited; the wheel speed signal output module is used for outputting a level signal corresponding to a wheel speed sensor signal; the overcurrent protection module is connected with one end of the current sampling resistor; one end of the current sampling resistor is connected with the wheel speed signal output module; the other end of the current sampling resistor is grounded.

Description

Technical Field

[0001] The utility model relates to the technical field of data acquisition, in particular to an analytical circuit for wheel speed sensor signals. Background Art

[0002] The output of the wheel speed sensor can be used to calculate the vehicle speed. At the same time, the vehicle's anti-lock braking system (ABS) will dynamically control the braking force on each tire according to the wheel speed of each tire to prevent the vehicle from locking its wheels during braking.

[0003] Current-type wheel speed sensors are widely used in vehicles, and are divided into standard current-type wheel speed sensors and AK protocol (ArbeitsKreis protocol) current-type wheel speed sensors. The standard current-type wheel speed sensor has two levels of current signals, a low-level signal of 7mA and a high-level signal of 14mA. The sensor transmits wheel speed information through changes in the frequency and duty cycle of the signal. The AK protocol current-type wheel speed sensor has three levels of current signals, a low-level current of 7mA, a medium-level current of 14mA, and a high-level current of 28mA. However, the wheel speed sensor signal analysis circuit in the prior art is not compatible with both the standard current-type wheel speed sensor and the AK protocol current-type wheel speed sensor. Therefore, how to make the analysis circuit compatible with both the standard current-type wheel speed sensor and the AK protocol current-type wheel speed sensor has become a technical problem that needs to be solved at present. Utility Model Content

[0004] In view of the above problems, the purpose of the present utility model is to provide a wheel speed sensor signal analysis circuit, so that the analysis circuit is compatible with both the standard current type wheel speed sensor and the AK protocol current type wheel speed sensor. The specific scheme is as follows:

[0005] A wheel speed sensor signal analysis circuit, the analysis circuit comprising:

[0006] Overcurrent protection module, current sampling resistor and wheel speed signal output module;

[0007] The overcurrent protection module is used to close the connection with the wheel speed signal output module when the wheel speed sensor signal is short-circuited;

[0008] The wheel speed signal output module is used to output a level signal corresponding to the wheel speed sensor signal;

[0009] The overcurrent protection module is connected to one end of the current sampling resistor;

[0010] One end of the current sampling resistor is connected to the wheel speed signal output module;

[0011] The other end of the current sampling resistor is grounded.

[0012] Optionally, the wheel speed signal output module includes:

[0013] A signal amplification submodule, a wheel speed signal high value output submodule and a wheel speed signal median value output submodule;

[0014] The signal amplification submodule is used to amplify the voltage signal converted by the current sampling resistor;

[0015] The wheel speed signal high value output submodule is used to output a high level when the wheel speed sensor signal is a high level current signal;

[0016] The wheel speed signal median output submodule is used to output a high level when the wheel speed sensor signal is a medium-level current signal;

[0017] The input end of the signal amplifying submodule is connected to one end of the current sampling resistor;

[0018] The output end of the signal amplification submodule is respectively connected to the input end of the wheel speed signal high value output submodule and the input end of the wheel speed signal medium value output submodule. Optionally, the signal amplification submodule includes an operational amplifier;

[0019] The input end of the operational amplifier is connected to one end of the current sampling resistor;

[0020] The output end of the operational amplifier is respectively connected to the input end of the wheel speed signal high value output submodule and the input end of the wheel speed signal middle value output submodule.

[0021] Optionally, the wheel speed signal high value output submodule includes a first comparator and a first power supply;

[0022] The first power supply is connected to the negative electrode of the first comparator;

[0023] The positive electrode of the first comparator is connected to the output end of the signal amplifying submodule.

[0024] Optionally, the wheel speed signal median output submodule includes a second power supply, a third power supply, a second comparator, a third comparator and an AND gate;

[0025] The output end of the signal amplifying submodule is connected to the negative electrode of the second comparator and the positive electrode of the third comparator respectively;

[0026] The positive electrode of the second comparator is connected to the second power supply;

[0027] The negative electrode of the third comparator is connected to the third power supply;

[0028] The output terminal of the second comparator is connected to the first input terminal of the AND gate;

[0029] The output terminal of the third comparator is connected to the second input terminal of the AND gate.

[0030] Optionally, the overcurrent protection module includes:

[0031] A first triode, a second triode, a first resistor, a second resistor, a third resistor, a fourth resistor and a fourth power supply;

[0032] The collector of the first transistor is connected to one end of the first resistor;

[0033] The emitter of the first transistor is connected to one end of the third resistor;

[0034] The base of the first transistor is connected to the other end of the third resistor;

[0035] The other end of the first resistor is connected to one end of the second resistor;

[0036] The other end of the second resistor is grounded;

[0037] The base of the second transistor is connected to the other end of the first resistor;

[0038] The collector of the second transistor is connected to the base of the first transistor;

[0039] The emitter of the second transistor is connected to the other end of the second resistor;

[0040] The other end of the third resistor is connected to one end of the fourth resistor;

[0041] The other end of the fourth resistor is connected to the fourth power supply.

[0042] Optionally, the first transistor and the second transistor are NPN transistors.

[0043] Optionally, the first power supply is a power supply with a voltage of 3 volts.

[0044] Optionally, the second power supply is a power supply with a voltage of 3 volts; and the third power supply is a power supply with a voltage of 1.5 volts.

[0045] Optionally, the amplification factor of the operational amplifier is 18.

[0046] Compared with the prior art, the utility model has the following beneficial effects:

[0047] By setting an overcurrent protection module, a current sampling resistor and a wheel speed signal output module, the overcurrent protection module is connected to one end of the current sampling resistor, one end of the current sampling resistor is connected to the wheel speed signal output module, and the other end of the current sampling resistor is grounded, so that when the wheel speed sensor signal received by the overcurrent protection module is short-circuited, the connection between the overcurrent protection module and the wheel speed signal output module is closed to prevent the wheel speed sensor signal from flowing into the subsequent circuit and causing the circuit components to burn, thereby protecting the analysis circuit. In addition, since the wheel speed signal output module is used to output a level signal corresponding to the wheel speed sensor signal, the analysis circuit can be compatible with both the standard current type wheel speed sensor and the AK protocol current type wheel speed sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0049] Figure 1 A schematic diagram of the structure of a wheel speed sensor signal analysis circuit provided by an embodiment of the utility model;

[0050] Figure 2 A schematic diagram of the structure of another wheel speed sensor signal analysis circuit provided by an embodiment of the utility model;

[0051] Figure 3 A schematic diagram of the structure of another wheel speed sensor signal analysis circuit provided by an embodiment of the utility model;

[0052] Figure 4 A schematic diagram of the structure of an overcurrent protection module provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0054] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the utility model and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0055] like Figure 1 As shown, the utility model provides a wheel speed sensor signal analysis circuit, the analysis circuit comprising:

[0056] Overcurrent protection module 101, current sampling resistor R1 and wheel speed signal output module 102;

[0057] The overcurrent protection module 101 is used to close the connection with the wheel speed signal output module 102 when the wheel speed sensor signal is short-circuited;

[0058] The wheel speed signal output module 102 is used to output a level signal corresponding to the wheel speed sensor signal;

[0059] The overcurrent protection module 101 is connected to one end of the current sampling resistor R1;

[0060] One end of the current sampling resistor R1 is connected to the wheel speed signal output module 102;

[0061] The other end of the current sampling resistor R1 is grounded.

[0062] The wheel speed sensor signal is input to the overcurrent protection module 101. When the overcurrent protection module 101 detects that the wheel speed sensor signal is short-circuited with the battery, it closes the connection with the wheel speed signal output module 102 to prevent the wheel speed sensor signal from flowing into the subsequent circuit when the wheel speed sensor signal is short-circuited to the 12V battery, causing a large current to be generated on the current sampling resistor R1, exceeding the rated power of the current sampling resistor R1, and burning the current sampling resistor R1, thereby protecting the circuit.

[0063] If the wheel speed sensor signal is not short-circuited with the battery, the wheel speed sensor signal flows out from the output end of the overcurrent protection module 101. The wheel speed sensor signal is converted by the current sampling resistor R1 to obtain a millivolt voltage signal, and the converted wheel speed sensor signal is input to the wheel speed signal output module 102 to obtain a recognition result of the wheel speed sensor signal, which includes that the wheel speed sensor signal is a low-level current, or the wheel speed sensor signal is a medium-level current, or the wheel speed sensor signal is a high-level current.

[0064] It should be noted that the resistance of the current sampling resistor R1 is 8Ω, the resistance accuracy is 1%, and the package size is 3.2mm×2.5mm. Taking the 3-level current signal of the AK protocol current type wheel speed sensor as an example, when the wheel speed sensor is a low-level current, the converted voltage signal is 56mv, when the wheel speed sensor is a medium-level current, the converted voltage signal is 112mv, and when the wheel speed sensor is a high-level current, the converted voltage signal is 224mv.

[0065] like Figure 2 As shown, in an optional embodiment, the wheel speed signal output module 102 includes:

[0066] A signal amplification submodule 201, a wheel speed signal high value output submodule 202 and a wheel speed signal median value output submodule 203;

[0067] The signal amplifying submodule 201 is used to amplify the voltage signal converted by the current sampling resistor R1;

[0068] The wheel speed signal high value output submodule 202 is used to output a high level when the wheel speed sensor signal is a high level current signal;

[0069] The wheel speed signal median output submodule 203 is used to output a high level when the wheel speed sensor signal is a medium-level current signal;

[0070] The input end of the signal amplifying submodule 201 is connected to one end of the current sampling resistor R1;

[0071] The output end of the signal amplification submodule 201 is connected to the input end of the wheel speed signal high value output submodule 202 and the input end of the wheel speed signal middle value output submodule 203 respectively.

[0072] The voltage signal obtained after conversion is input to the input end of the signal amplification submodule 201. After amplification by the signal amplification submodule 201, the signal amplification submodule 201 outputs the signal to the input end of the wheel speed signal high value output submodule 202 and the input end of the wheel speed signal median output submodule 203. After receiving the amplified voltage signal, the wheel speed signal high value output submodule 202 determines whether the wheel speed sensor signal is a high-level current signal. If so, it outputs a high level, otherwise it outputs a low level. After receiving the amplified voltage signal, the wheel speed signal median output submodule 203 determines whether the wheel speed sensor signal is a medium-level current signal. If so, it outputs a high level, otherwise it outputs a low level.

[0073] like Figure 3 As shown, in an optional embodiment, the signal amplification submodule 201 includes an operational amplifier U1;

[0074] The input end of the operational amplifier U1 is connected to one end of the current sampling resistor R1;

[0075] The output end of the operational amplifier U1 is connected to the input end of the wheel speed signal high value output submodule 202 and the input end of the wheel speed signal middle value output submodule 203 respectively.

[0076] The input end of the operational amplifier U1 is connected to one end of the current sampling resistor R1, and the output end is respectively connected to the input end of the wheel speed signal high value output submodule 202 and the input end of the wheel speed signal median output submodule 203, so that the voltage signal is output to the wheel speed signal high value output submodule 202 and the wheel speed signal median output submodule 203 after being amplified by the operational amplifier U1.

[0077] In an optional embodiment, the gain factor of the operational amplifier U1 is 18.

[0078] Taking the 3-level current signal of the AK protocol current type wheel speed sensor as an example, when the wheel speed sensor is a low-level current, the amplified voltage signal is 56mv*18=1.008V, when the wheel speed sensor is a medium-level current, the amplified voltage signal is 112mv*18=2.016V, and when the wheel speed sensor is a high-level current, the amplified voltage signal is 224mv*18=4.032V.

[0079] In an optional embodiment, the wheel speed signal high value output submodule 202 includes a first comparator U2 and a first power supply V1;

[0080] The first power supply V1 is connected to the negative electrode of the first comparator U2;

[0081] The positive electrode of the first comparator U2 is connected to the output end of the signal amplifying submodule 201 .

[0082] The amplified voltage signal is input to the positive electrode of the first comparator U2, and the first power supply V1 is connected to the negative electrode of the first comparator U2, so as to set the reference voltage of the first comparator U2 through the first power supply V1. Any voltage value is selected from the preset voltage range of the first power supply V1 as the voltage value of the first power supply V1, and any voltage value in the preset voltage range of the first power supply V1 is to enable the first comparator U2 to output a high-level voltage only when the wheel speed sensor signal is a high-level current signal. Taking the voltage signal amplified by the signal amplification submodule 201 as 18 times that before amplification as an example, the preset voltage range of the first power supply V1 is greater than 2.016V and less than 4.032V.

[0083] Since the first comparator U2 outputs a low level when the amplified voltage signal is less than the reference voltage of the first comparator U2, and outputs a high level when the amplified voltage signal is greater than the reference voltage, by selecting a voltage from the preset voltage range of the first power supply V1 as the voltage value of the first power supply V1, the first comparator U2 is set to output a high-level reference voltage when the wheel speed sensor signal is a high-level current signal, so as to realize that the wheel speed signal high-value output submodule 202 outputs a high level when the wheel speed sensor signal is a high-level current signal.

[0084] In an optional embodiment, the first power supply V1 is a power supply with a voltage of 3V.

[0085] When the first power supply V1 is a power supply with a voltage of 3V, the reference voltage of the first comparator U2 is greater than 3V. Taking the 3-level current signal of the AK protocol current type wheel speed sensor as an example, when the wheel speed sensor is a low-level current, the amplified voltage signal is 1.008V, which is less than 3V, so the first comparator U2 outputs a low level. When the wheel speed sensor is a medium-level current, the amplified voltage signal is 2.016V, which is less than 3V, so the first comparator U2 outputs a low level. When the wheel speed sensor is a high-level current, the amplified voltage signal is 4.032V, which is greater than 3V, so the first comparator U2 outputs a high level.

[0086] In an optional embodiment, the wheel speed signal median output submodule 203 includes a second power supply V2, a third power supply V3, a second comparator U3, a third comparator U4 and an AND gate U5;

[0087] The output end of the signal amplifying submodule 201 is connected to the negative electrode of the second comparator U3 and the positive electrode of the third comparator U4 respectively;

[0088] The positive electrode of the second comparator U3 is connected to the second power supply V2;

[0089] The cathode of the third comparator U4 is connected to the third power supply V3;

[0090] An output terminal of the second comparator U3 is connected to a first input terminal of an AND gate U5;

[0091] An output terminal of the third comparator U4 is connected to a second input terminal of the AND gate U5 .

[0092] The negative electrode of the second comparator U3 and the positive electrode of the third comparator U4 are respectively connected to the output end of the signal amplification submodule 201, so that the second comparator U3 and the third comparator U4 can receive the amplified voltage signal. The second power supply V2 is connected to the positive electrode of the second comparator U3 to form a reference voltage of the second comparator U3. Any voltage value is selected from the preset voltage range of the second power supply V2 as the voltage of the second power supply V2. Any voltage within the preset voltage range of the second power supply V2 is a voltage that enables the second comparator U3 to output a high level when the wheel speed sensor signal is a low-level current signal or a medium-level current signal. Taking the voltage signal after amplification by the signal amplification submodule 201 as 18 times that before amplification as an example, the preset voltage range of the second power supply V2 is greater than 2.016V and less than 4.032V.

[0093] The third power supply V3 is connected to the negative electrode of the third comparator U4 to form a reference voltage of the third comparator U4. Any voltage value is selected from the preset voltage range of the third power supply V3 as the voltage of the third power supply V3. Any voltage within the preset voltage range of the third power supply V3 is a voltage that enables the third comparator U4 to output a high level when the wheel speed sensor signal is a medium-level current signal or a high-level current signal. For example, if the voltage signal after amplification by the signal amplification submodule 201 is 18 times that before amplification, the preset voltage range of the third power supply V3 is greater than 1.008V and less than 2.016V.

[0094] Since the output end of the second comparator U3 is connected to the first input end of the AND gate U5, the output end of the third comparator U4 is connected to the second input end of the AND gate U5, and the second comparator U3 outputs a high level when the wheel speed sensor signal is a low-level current signal or a medium-level current signal, and the third comparator U4 outputs a high level when the wheel speed sensor signal is a medium-level current signal or a high-level current signal. Therefore, when the wheel speed sensor signal is a medium-level current signal, the second comparator U3 and the third comparator U4 both output a high level, so that the AND gate U5 outputs a high level. When the wheel speed sensor signal is a high-level current signal, the second comparator U3 outputs a low level, and the third comparator U4 outputs a high level, so that the AND gate U5 outputs a low level. When the wheel speed sensor signal is a low-level current signal, the second comparator U3 outputs a high level, and the third comparator U4 outputs a low level, so that the AND gate U5 outputs a low level. In this way, the wheel speed signal median output submodule 203 outputs a high level when the wheel speed sensor signal is a medium-level current signal.

[0095] For ease of understanding, the truth table of the wheel speed signal median output submodule 203 and the wheel speed signal high value output submodule 202 is shown in Table 1.

[0096]

[0097] Table 1

[0098] The processor is respectively connected to the output end of the wheel speed signal median output submodule 203 and the output end of the wheel speed signal high value output submodule 202. After the processor receives the signals output by the wheel speed signal median output submodule 203 and the wheel speed signal high value output submodule 202, if the wheel speed sensor is an AK protocol current type wheel speed sensor, the processor parses the wheel speed information through the level signal output by the wheel speed signal high value output submodule 202, and parses the direction and air gap information through the level signal output by the wheel speed signal median output submodule 203. If the wheel speed sensor is a standard current type wheel speed sensor, the processor parses the wheel speed information through the frequency and duty cycle changes of the level signal output by the wheel speed signal median output submodule 203.

[0099] In an optional embodiment, the second power supply V2 is a power supply with a voltage of 3 volts; the third power supply V3 is a power supply with a voltage of 1.5 volts.

[0100] When the voltage of the second power supply V2 is 3V, and the voltage of the third power supply V3 is 1.5V, the reference voltage of the second comparator U3 is less than 3V, and the reference voltage of the third comparator U4 is greater than 1.5V. Taking the 3-level current signal of the AK protocol current type wheel speed sensor as an example, when the wheel speed sensor is a low-level current, since the amplified voltage signal is 1.008V, the second comparator U3 outputs a high level, the third comparator U4 outputs a low level, and the AND gate U5 outputs a low level. When the wheel speed sensor is a medium-level current, since the amplified voltage signal is 2.016V, the second comparator U3 outputs a high level, the third comparator U4 outputs a high level, and the AND gate U5 outputs a high level. When the wheel speed sensor is a high-level current, since the amplified voltage signal is 4.032V, the second comparator U3 outputs a low level, the third comparator U4 outputs a high level, and the AND gate U5 outputs a low level.

[0101] like Figure 4 As shown, in an optional embodiment, the overcurrent protection module 101 includes:

[0102] A first transistor Q1, a second transistor Q2, a first resistor R2, a second resistor R3, a third resistor R4, a fourth resistor R5 and a fourth power supply V4;

[0103] The collector of the first transistor Q1 is connected to one end of the first resistor R2;

[0104] The emitter of the first transistor Q1 is connected to one end of the third resistor R4;

[0105] The base of the first transistor Q1 is connected to the other end of the third resistor R4;

[0106] The other end of the first resistor R2 is connected to one end of the second resistor R3;

[0107] The other end of the second resistor R3 is grounded;

[0108] The base of the second transistor Q2 is connected to the other end of the first resistor R2;

[0109] The collector of the second transistor Q2 is connected to the base of the first transistor Q1;

[0110] The emitter of the second transistor Q2 is connected to the other end of the second resistor R3;

[0111] The other end of the third resistor R4 is connected to one end of the fourth resistor R5;

[0112] The other end of the fourth resistor R5 is connected to the fourth power source V4.

[0113] The resistance of the first resistor R2 is 4.7k, the resistance of the second resistor R3 is 100k, the resistance of the third resistor R4 is 100k, the resistance of the fourth resistor R5 is 2.7k, the voltage of the fourth power supply V4 is 5V, and the first transistor Q1 and the second transistor Q2 are NPN transistors. One end of the third resistor R4 is connected to the emitter of the first transistor Q1, and the other end of the third resistor R4 is respectively connected to one end of the fourth resistor R5 and the base of the first transistor, and the other end of the fourth resistor R5 is connected to the fourth power supply V4. When the circuit starts working, the third resistor R4, the fourth resistor R5 and the current sampling resistor R1 form a voltage divider circuit, so that the third resistor R4 and the fourth resistor R5 divide the 5V to ensure that the first transistor Q1 is in the on state.

[0114] One end of the first resistor R2 is connected to the collector of the first transistor Q1, the other end of the first resistor R2 is respectively connected to one end of the second resistor R3 and the collector of the second transistor Q2, the other end of the second resistor R3 is connected to the emitter of the second transistor Q2, and the other end of the second resistor R3 is grounded, so that the first resistor R2 and the second resistor R3 divide the output signal of the wheel speed sensor. When the output signal of the wheel speed sensor is not short-circuited with the battery, the maximum voltage of the output signal of the wheel speed sensor is the voltage corresponding to the high-level current, which is 224mV. After this voltage is divided by the first resistor R2 and the second resistor R3, the second transistor Q2 cannot be turned on, and the second transistor Q2 is in a closed state, so that the wheel speed sensor signal can be normally input to the subsequent circuit. When the wheel speed sensor output signal is short-circuited with the 12V battery, the current on the current sampling resistor R1 exceeds 91mA. After the first resistor R2 and the second resistor R3 divide the wheel speed sensor output signal, the second transistor Q2 is turned on and the base of the first transistor Q1 is short-circuited to the ground to avoid burning the devices in the subsequent circuit.

[0115] By setting an overcurrent protection module 101, a current sampling resistor R1 and a wheel speed signal output module 102, the overcurrent protection module 101 is connected to one end of the current sampling resistor R1, one end of the current sampling resistor R1 is connected to the wheel speed signal output module 102, and the other end of the current sampling resistor R1 is grounded, so that when the wheel speed sensor signal received by the overcurrent protection module 101 is short-circuited, the connection between the overcurrent protection module 101 and the wheel speed signal output module 102 is closed to prevent the wheel speed sensor signal from flowing into the subsequent circuit and causing the circuit components to burn, thereby protecting the analysis circuit. In addition, since the wheel speed signal output module 102 is used to output a level signal corresponding to the wheel speed sensor signal, the analysis circuit can be compatible with both the standard current type wheel speed sensor and the AK protocol current type wheel speed sensor.

[0116] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles disclosed herein.

Claims

1. A wheel speed sensor signal analysis circuit, characterized in that: The analysis circuit comprises: Overcurrent protection module, current sampling resistor and wheel speed signal output module; The overcurrent protection module is used to close the connection with the wheel speed signal output module when the wheel speed sensor signal is short-circuited; The wheel speed signal output module is used to output a level signal corresponding to the wheel speed sensor signal; The overcurrent protection module is connected to one end of the current sampling resistor; One end of the current sampling resistor is connected to the wheel speed signal output module; The other end of the current sampling resistor is grounded.

2. The analytical circuit according to claim 1, characterized in that: The wheel speed signal output module comprises: A signal amplification submodule, a wheel speed signal high value output submodule and a wheel speed signal median value output submodule; The signal amplification submodule is used to amplify the voltage signal converted by the current sampling resistor; The wheel speed signal high value output submodule is used to output a high level when the wheel speed sensor signal is a high level current signal; The wheel speed signal median output submodule is used to output a high level when the wheel speed sensor signal is a medium-level current signal; The input end of the signal amplifying submodule is connected to one end of the current sampling resistor; The output end of the signal amplification submodule is respectively connected to the input end of the wheel speed signal high value output submodule and the input end of the wheel speed signal medium value output submodule.

3. The analytical circuit according to claim 2, characterized in that: The signal amplification submodule includes an operational amplifier; The input end of the operational amplifier is connected to one end of the current sampling resistor; The output end of the operational amplifier is respectively connected to the input end of the wheel speed signal high value output submodule and the input end of the wheel speed signal middle value output submodule.

4. The analytical circuit according to claim 2, characterized in that: The wheel speed signal high value output submodule includes a first comparator and a first power supply; The first power supply is connected to the negative electrode of the first comparator; The positive electrode of the first comparator is connected to the output end of the signal amplifying submodule.

5. The analytical circuit according to claim 2, characterized in that: The wheel speed signal median output submodule includes a second power supply, a third power supply, a second comparator, a third comparator and an AND gate; The output end of the signal amplifying submodule is connected to the negative electrode of the second comparator and the positive electrode of the third comparator respectively; The positive electrode of the second comparator is connected to the second power supply; The negative electrode of the third comparator is connected to the third power supply; The output terminal of the second comparator is connected to the first input terminal of the AND gate; The output terminal of the third comparator is connected to the second input terminal of the AND gate.

6. The analytical circuit according to claim 1, characterized in that: The overcurrent protection module comprises: A first triode, a second triode, a first resistor, a second resistor, a third resistor, a fourth resistor and a fourth power supply; The collector of the first transistor is connected to one end of the first resistor; The emitter of the first transistor is connected to one end of the third resistor; The base of the first transistor is connected to the other end of the third resistor; The other end of the first resistor is connected to one end of the second resistor; The other end of the second resistor is grounded; The base of the second transistor is connected to the other end of the first resistor; The collector of the second transistor is connected to the base of the first transistor; The emitter of the second transistor is connected to the other end of the second resistor; The other end of the third resistor is connected to one end of the fourth resistor; The other end of the fourth resistor is connected to the fourth power supply.

7. The analytical circuit according to claim 6, characterized in that: The first transistor and the second transistor are NPN transistors.

8. The analytical circuit according to claim 4, characterized in that: The first power source is a power source with a voltage of 3 volts.

9. The analytical circuit according to claim 5, characterized in that: The second power supply is a power supply with a voltage of 3 volts; the third power supply is a power supply with a voltage of 1.5 volts.

10. The analytical circuit according to claim 3, characterized in that: The amplification factor of the operational amplifier is 18.

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